The invention relates to a static micromixer with a mixing chamber and a guide component which is arranged upstream of the mixing chamber for the separate admission to the mixing chamber of the fluids to be mixed or to be dispersed and through which slot-like channels extend at an angle with respect to the longitudinal axis of the micromixer.
DE 44 16 343 C2 discloses a micromixer including at least one mixing chamber and a guide component arranged upstream of the mixing chamber for the separate admission to a mixing chamber of fluids to be mixed, wherein the guide component has dimensions in the millimeter range and is composed of several superimposed foils of which each has a thickness of about 100 xcexcm and which include microstructure-channels. The straight supply channels have a uniform cross-section and extend at an angle to the longitudinal axis of the micromixer wherein the channels of adjacent foils cross one another without communicating and extend to a common mixing chamber. The channels have a width, which is less than 250 xcexcm and a height of about 70 xcexcm. The thickness of the web between the channels is about 15 xcexcm. The individual foils may be joined for example by diffusion welding to form a homogeneous vacuum tight and pressure tight microstructure body. A cover plate is disposed on the first and, respectively, the last foil.
A similar micromixer, which has curved parallel supply channels leading to the mixing chamber for two fluids to be mixed or dispersed but otherwise is of the same design and operating principle, is described in DE 195 40 292 C1. With this arrangement, a rapid mixing in the mixing chamber, which is also uniform over the whole flow cross-section, is to be achieved. The guide channels have a uniform cross-section with widths of less than 250 xcexcm; the foils into which the channel structures are formed, have a thickness of about 100 xcexcm.
Another possibility to optimize the mixing process is disclosed in WO 97/17130. By a combination of individual channels to form a slot-like channel per foil, the micromixer achieves, by the elimination of the webs between the individual channels, a more advantageous ratio of volume flow to channel wall surface area and, consequently, a reduction of the friction losses in guide component.
It is the object of the present invention to provide, on the basis of the last mentioned state of the art, a guide component for the admission of the fluids to be mixed to the mixing chamber of a static mixer of the type as described, whereby the pressure losses of the fluids in the guide component between the inlet and the common outlet side are further reduced. At the same time, an at least equal or possibly improved mixing quality (effectiveness of the mixing process) should be achieved.
In a static micromixer which comprises at least one mixing chamber and one guide component disposed upstream of the mixing chamber and which includes channels extending therethrough at an angle to the longitudinal axis of the micromixer, so that the channels of alternate layers intersect without communicating with each other, the cross-section of the channels decreases steadily from the entrance end to the exit end of the guide component so as to reduce the pressure losses of the fluid flowing through the channels for mixing in the mixing chamber.
The individual admission channels extend from the at least two fluid supply chambers at an angle to the longitudinal axis of the micromixer. Channels of adjacent layers which contain fluids from different supply chambers, intersect without communication and lead to the mixing chamber by way of a common cross-sectional discharge area. The openings of the slot-like channels are disposed on top of one another in an aligned fashion. With the introduction of a second mixing stage in the mixing chamber in the form of a structure which divides the flow (for example, a grid), the turbulence in the mixing chamber and the mixing effect are increased.
With an increased channel flow cross-section at the entrance end of the channels, the flow speed of the fluid flowing therein is relatively low with an equal volume flow. With the greater channel cross-section and the lower flow speed, the friction lost in the fluids between the entrance and the exit area of the guide component is reduced. Also, with the locally wider channels, the chances of the channels becoming clogged are reduced.
An embodiment of the micromixer according to the invention as well as a method of manufacturing the same will be described below on the basis of the accompanying drawings: